Lecture #2 Flashcards
What is an atom?
Smallest unit of matter which can partake in a chemical reaction
What is formed when two or more atoms are joined together?
A molecule
Does a molecule have to be composed of all different atoms?
No, it can contain same molecules eg. O2
What 3 things does is every atom composed of?
Nucleus, Proton, Neutron
Protons and neutrons are equal when…?
The atom is stable
The atomic number is the number of…?
Protons
The nucleus will always carry a net positive charge because?
Neutrons have no charge so there is just positive charge in the nucleus
Electrons are located in….?
Orbitals outside of the nucleus
Why are nuclear contents referred to as stable?
Because they do not participate in chemical reactions
When an atom loses an electron, it has what type of charge?
Net positive
When an atom has an overall negative or positive charged, it is referred to as an?
Ion
Atoms carrying a negative charged is called? Positive?
Anion, Cation
A chemical bond is formed when
The outer shell electrons interact
What are the 3 types of chemical bonds found in living organisms?
- Covalent
- Ionic
- Hydrogen
Are covalent bonds strong or weak?
Very strong
How are covent bonds formed?
When two atoms share electrons with their outer shell
What type of bond does water have? Between what elements?
Covalent bond between hydrogen and oxygen
How are ionic bonds formed?
As a result of the attractive force between ions of opposite force, they do not share electrons, rather donate
Are hydrogen bonds weak or strong?
Weaker than covalent
What element is most common in human cells? Why?
Carbon, because it has sides that can covalent bond
How is a hydrogen bond formed?
When hydrogen is covalently bonded to oxygen or another electron loving molecule
What are polar molecules?
Unequal sharing of electrons
What type of sharing occurs in hydrogen bonds? Why?
Polar molecules result because the atom bound to hydrogen is electron loving, it holds it closer to the nucleus then hydrogen resulting in unequal sharing
Explain which atom receives partial negative/positive charge on polar molecules
Partial positive for hydrogen
Partial negative on the electron loving atom
Are hydrogen bonds strong or weak?
Weakest out of the 3
What are organic compounds?
Compounds containing carbon
What are inorganic compounds?
Compounds that do not contain carbon
What type of compounds do organisms require to live and reproduce?
Inorganic
What allows water to be so able to dissolve many things?
The partial positive and negative bonds allow it to dissolve many things
What molecule is called a partial solvent? What does that mean?
H2O because it dissolved material and electron are not equally shared
How many hydrogen bonds can H2O have max?
4
What are 4 reasons why living things make such good use of water?
- Water is an excellent solvent
- Every H2O molecule can form hydrogen bonds with other water molecules
- Water is a great temperature buffer because of its strong hydrogen bonds
- Water is easily split into its component ions H+ and OH-
Why is water a great solvent?
Because water can dissolve many ionic compounds
A solution with water is formed when?
The partial positive region within H2O molecules surround ions and partial negative region of H2O molecules surround positive ions, holding them in a solution
What gives water such a high boiling point?
Because hydrogen is able to have 4 bonds allowing it to form networks of interconnected molecules
What allows water to stay liquid in most places it is found on earth?
It’s high boiling point
Why is water such a great temperature buffer?
Because of its strong hydrogen bonds
What allows water to play key roles in many chemical reactions?
Its ability to be easily split into its component ions H+ and OH-
What outer 4 electrons allow it to form what?
4 covalent bonds with lots of different atoms
What are the 4 major classes of organic compounds found in living things?
- Carbohydrates
- Lipids
- Proteins
- Nucleic Acids
What is the energy source that can immediately used by cells?
Carbs
Are carbohydrates polar or non polar?
Polar (so they dissolve in water)
What elements do carbohydrates always have?
C, H and O
What ratio is carbohydrates usually found in
C, H2, O
What are the 3 major groups of carbs?
- Monosaccharide
- Disaccharide
- Polysaccharide
What are two examples of monosaccharides?
Glucose and Fructose
What does monosaccharide mean?
One sugar
What is an example of a disaccharide? What is it made up of?
Sucrose, made from glucose and fructose
What does disaccharide mean
Two sugars
What does ‘Like Dissolved Like’ mean?
ex. H2O is polar as well as sugar therefore it dissolves well
What is a polysaccharide made up of?
Many sugars (hundreds)
Which type of carb is often no water soluble? Why?
Polysaccharides because they are often too large
What are 3 examples of polysaccharides?
Starch, Cellulose and Glycogen
What type of polysaccharide allows us to store excess sugar?
Glycogen
What are 3 types of lipids?
- Fats
- Complex lipids (phospholipids)
- Steroids
Why are lipids heterogenous?
Because many things represent it
Where are lipids found in a cell?
Cell membrane, phospholipid bilayer
Why are lipids used as a means of energy storage?
Because a gram of fat can store 2x the mount of energy compared to a sugar
What does are body store extra energy as
Lipids
Why are lipids non reactive to water?
Because they are non polar
What are fats composed of?
A glycerol molecule and 1-3 fatty acids?
What are 3 types of fats? What are they composed of?
Monoacylglyceride- Glycerol and 1 Fatty Acid
Diacylglyceride- Glycerol and 2 Fatty Acids
Triacylglyceride- Glycerol and 3 Fatty Acids
Fatty acids can be different by whether it is…….?
Saturated or Unsaturated
What is the difference between saturated and unsaturated fats
Saturated= No double bonds, and saturated with a hydrogen atom
Non saturated= Has at least 1 double bond, fewer hydrogen atoms (less saturated with hydrogen)
What are complex lipids made up of?
Glycerol, 2 Fatty Acids and a phosphate group
What makes steroids structurally distinct from other lipids
It’s 4 ring structure
Steroids are found in mainly?
Eukaryotes not prokaryotes
What are two examples of steroids
Cholesterol and Vitamin D
Proteins are formed from
Amino acids
How many known amino acids are there?
20
What are all proteins (amino acids) composed of
Carbon, Oxygen, Hydrogen and Nitrogen
Each amino acid has what 3 molecule compounds?
Amino group, Carboxyl group and a side group (which is different on each AA)
What determines the chemical properties of the amino acid?
The side group R-
What type of bond holds the amino acids together when forming a protein? Are they ionic, covalent or hydrogen bonds)
Peptide bond which are covalent (can be other)
What are short chains of AA called? Long chains?
Peptides, Polypeptide which are proteins
What determines the shape of the protein?
The specific amino acid sequence
What two things are proteins important for in a cell
- Structural components (membrane channels)
2. Enzymes which increase the rate at which chemical reactions occur in the cell
What are nucleic acids made up of?
Nucleotides
What are the 3 components are nucleotides are made up of?
Nitrogenous base, Pentose sugar and a phosphate group
What are two nitrogenous base ‘groups’
- purines
2. pyrimidines
Which nitrogenous base contains two rings. Which contains one?
2 rings- purines
1 ring- pyrimidines
What are two types of purines?
Adenine and Guanine
What are 3 types of pyrimidines?
Cytosine, Thymine and Uracil
What is a pentose sugar?
A 5 carbon sugar
What are two types of pentose sugars?
Ribose and Deoxyribose
What is the phosphate group in a nucleotide attached to and what does it serve as?
Attached to the nucleotide and serves as a site for attachment for the next nucleotide
What are two types of nucleic acids
- Deoxyribonucleic acid (DNA)
2. Ribonucleic acid (RNA)
What is the difference between DNA and RNA
DNA- composed of Deoxyribose sugar
RNA- composed of Ribose sugar
Which Nucleic acid is single stranded, which is double?
DNA- double
RNA- single
How is each strand of DNA held together?
A hydrogen bond
What in DNA forms the genetic instructions for the organism
The oder of nucleotide sequence which is very specific
Which nucleotides make up DNA vs RNA
DNA- A,C,T,G
RNA- A, C, U and G
What does RNA do?
Communicates instructions when forming DNA
